With light-weighting initiatives creating thinner container walls, manufacturers have attempted to alleviate associated problems with container strength reductions. Thin walled plastic containers can be prone to deforming or “ovalization,” and may not be suitable for vending purposes as the force from such a drop can cause container rupture. Also, over a period of time, thin-walled containers with liquid contents can lose a fraction of their contents more rapidly than comparatively thicker-walled containers, which can lead to increased internal vacuum and deformation.
Thin walled plastic containers can be used for many purposes, including being filled with “hot” or “cold” contents. With “hot-fill” packages, containers are commonly filled with a heated or “hot” liquid product and capped while the product contents remain at an elevated temperature. As the product contents cool, the associated reduction in the volume of the contents can create a vacuum pressure within the container—i.e., an internal pressure that is less than the surrounding atmospheric pressure. If the container is comprised of a molded plastic, portions of the container walls may distort inwardly as the contents cool.
To address these concerns associated with containers, including thin-walled containers, whether for either “hot” or “cold” filling applications, some conventional containers are filled with an inert gas, such as nitrogen, prior to capping. This method adds internal pressure and external rigidity for a time. Further, some containers provide ribs, grooves, or relatively thicker wall portions on the container walls to strengthen the walls so as to reduce the effects of distortion. Still others may additionally utilize one or more vacuum panels to help account for or otherwise control the amount of distortion associated with an anticipated vacuum pressure. However, in addition to increasing the complexity of the container and manufacturing process, some or all of the aforementioned measures may be seen as aesthetically displeasing and/or may require additional material, which can contribute to increased weight and cost.